Remove non-existing include in ROS2 tests

[jhanca-robotecai]

What does this PR do?

Tests would not build with the more recent o3de development due to some changes in includes:

[build] /home/jhanca/devroot/o3de-extras/Gems/ROS2/Code/Tests/Frame/ROS2FrameComponentTest.cpp:23:10: fatal error: 'AzToolsFramework/Commands/PreemptiveUndoCache.h' file not found
[build] #include <AzToolsFramework/Commands/PreemptiveUndoCache.h>
[build]          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[build] 1 error generated.
[build] ninja: build stopped: subcommand failed.

This PR fixes it by removing this include.

How was this PR tested?

The code builds now correctly and the test passes.

[proc] Executing command: /usr/bin/ctest -j16 -C profile -T test --output-on-failure -R ^Gem\:\:ROS2\.Frame\.Tests\.main\:\:TEST_RUN$
[ctest]    Site: jhanca-buntu
[ctest]    Build name: Linux-clang++
[ctest] Create new tag: 20240424-0626 - Experimental
[ctest] Test project /home/jhanca/devroot/projects/R2PT/build/linux
[ctest]     Start 148: Gem::ROS2.Frame.Tests.main::TEST_RUN
[ctest] 1/1 Test #148: Gem::ROS2.Frame.Tests.main::TEST_RUN ...   Passed    0.83 sec
[ctest] 
[ctest] 100% tests passed, 0 tests failed out of 1
[ctest] 
[ctest] Label Time Summary:
[ctest] FRAMEWORK_googletest    =   0.83 sec*proc (1 test)
[ctest] SUITE_main              =   0.83 sec*proc (1 test)
[ctest] 
[ctest] Total Test time (real) =   0.98 sec
[ctest] CTest finished with return code 0

[jhanca-robotecai]

@amzn-changml I saw you tried to run the tests, but those failed. Do you think we can proceed with an override? The change is made in ROS2 gem, which is not included in the tests, which means this change cannot trigger problems for Jenkins.

[jhanca-robotecai]

Force-pushed on top of the current development

[jhanca-robotecai]

The tests are now successful, but they have not been reported back from Jenkins to Github.

[amzn-changml]

I confirm that AR was ran successfully after the force push. Bypassing AR and merging in